Comparing the climate effect of emissions of short- and long-lived climate agents

Multi-gas climate agreements require a metric by which emissions of gases with different lifetimes and radiative properties can be placed on a common scale. The Kyoto Protocol to the United Nations Framework Convention on Climate Change uses the global warming potential (GWP) as such a metric. The GWP has attracted particular criticism as being inappropriate in the context of climate policy which seeks to restrict warming below a given target, because it gives equal weight to emissions irrespective of the target and the proximity to the target. The use of an alternative metric, the time-dependent global temperature change potential (GTP), is examined for its suitability and the prospects for it including very short-lived species. It retains the transparency and relative ease of use, which are attractive features of the GWP, but explicitly includes a dependence on the target of climate policy. The weighting of emissions using the GTP is found to be significantly dependent on the scenarios of future emissions and the sensitivity of the climate system. This may indicate that the use of any GTP-based weighting in future policymaking would necessitate regular revisions, as the global-mean temperature moves towards a specified target.     

Variation in the response to manipulation of post-mortem glycolysis in beef muscles by low-voltage electrical stimulation and conditioning temperature

The aim of this study was to investigate how manipulation of glycolytic rate by post-mortem processing conditions influences quality of aged beef of two bovine muscles of different physiological character, longissimus dorsi (LD) and adductor (AD). Post-mortem glycolysis was manipulated by low-voltage electrical stimulation (LV-ES) of half carcasses and by chilling rate of the muscles. Multivariate statistical analysis was used to visualise the data, while ANOVA was used to identify significant effects and interactions. As expected there was a significant effect of LV-ES on the pH decline in the first hours post-mortem in both muscles. Moreover, significant effects of LV-ES on WB shear force measured 2 and 8 days after slaughter were observed for LD at both chilling temperatures, while for AD no effect on WB shear force was observed. Furthermore, the results revealed a large individual variation in the response of LV-ES on both pH decline and WB shear force, and this variation did not always correlate for the two responses. Some animals showed no response of LV-ES on pH decline, but still had an improved WB shear force, and vice versa. The results from this study indicate that there probably are other mechanisms than accelerated pH decline and prevention of cold-shortening, by which LV-ES can affect meat tenderness.     

Comparison of driving simulator performance with real driving after alcohol intake: A randomised,single blind,placebo-controlled,cross-over trial

The purpose of this study was to establish and validate a driving simulator method for assessing drug effects on driving. To achieve this, we used ethanol as a positive control, and examined whether ethanol affects driving performance in the simulator, and whether these effects are consistent with performance during real driving on a test track, also under the influence of ethanol. Twenty healthy male volunteers underwent a total of six driving trials of 1 h duration; three in an instrumented vehicle on a closed-circuit test track that closely resembled rural Norwegian road conditions, and three in the simulator with a driving scenario modelled after the test track. Test subjects were either sober or titrated to blood alcohol concentration (BAC) levels of 0.5 g/L and 0.9 g/L. The study was conducted in a randomised, cross-over, single-blind fashion, using placebo drinks and placebo pills as confounders. The primary outcome measure was standard deviation of lateral position (SDLP; “weaving”). Eighteen test subjects completed all six driving trials, and complete data were acquired from 18 subjects in the simulator and 10 subjects on the test track, respectively. There was a positive dose–response relationship between higher ethanol concentrations and increases in SDLP in both the simulator and on the test track (p < 0.001 for both). In the simulator, this dose–response was evident already after 15 min of driving. SDLP values were higher and showed a larger inter-individual variability in the simulator than on the test track. Most subjects displayed a similar relationship between BAC and SDLP in the simulator and on the test track; however, a few subjects showed striking dissimilarities, with very high SDLP values in the simulator. This may reflect the lack of perceived danger in the simulator, causing reckless driving in a few test subjects. Overall, the results suggest that SDLP in the driving simulator is a sensitive measure of ethanol impaired driving. The comparison with real driving implies relative external validity of the simulator.     

Measurement and simulation of partial switching in ferroelectric PZT thin-films

Abstract

In digital memory applications, metal ferroelectric metal (MFM) capacitors are typically fully switched from one polarization state to the other, with the difference in displacement current allowing determination of the cell state. However, by applying a pulse of insufficient amplitude and/or duration to fully switch the ferroelectric, such a device may be partially polarized. Here, the measurement of partial switching in sol-gel derived PZT MFM capacitors due to applied voltage pulses is reported. SPICE, a commonly used circuit simulation program, has been modified to incorporate a ferroelectric capacitor device model. The MFM device model added to SPICE is reviewed, and the simulation of partial switching is demonstrated. Simulation results modeling the PE hysteresis loops and switching transients due to applied voltage steps closely match those measured in the laboratory. We conclude with the modeling of incomplete switching due to applied pulses of insufficient amplitude to cause polarization saturation, which is attributed to the polycrystalline nature of the thin-films.     

Climate effects of emission standards: the case for gasoline and diesel cars

Passenger transport affects climate through various mechanisms involving both long-lived and short-lived climate forcers. Because diesel cars generally emit less CO(2) than gasoline cars, CO(2) emission taxes for vehicle registrations and fuels enhance the consumer preference for diesel cars over gasoline cars. However, with the non-CO(2) components, which have been changed and will be changed under the previous and upcoming vehicle emission standards, what does the shift from gasoline to diesel cars mean for the climate mitigation? By using a simple climate model, we demonstrate that, under the earlier emissions standards (EURO 3 and 4), a diesel car causes a larger warming up to a decade after the emissions than a similar gasoline car due to the higher emissions of black carbon and NO(X) (enhancing the O(3) production). Beyond a decade, the warming caused by a diesel car becomes, however, weaker because of the lower CO(2) emissions. As the latter emissions standards (EURO 5 and 6) are phased in, the short-term warming due to a diesel car becomes smaller primarily due to the lower black carbon emissions. Thus, although results are subject to restrictive assumptions and uncertainties, the switch from gasoline to diesel cars encouraged by CO(2) taxes does not contradict with the climate mitigation focusing on long-term consequences.     

Cabozantinib Is Effective in Melanoma Brain Metastasis Cell Lines and Affects Key Signaling Pathways

Melanomas have a high potential to metastasize to the brain. Recent advances in targeted therapies and immunotherapies have changed the therapeutical landscape of extracranial melanomas. However, few patients with melanoma brain metastasis (MBM) respond effectively to these treatments and new therapeutic strategies are needed. Cabozantinib is a receptor tyrosine kinase (RTK) inhibitor, already approved for the treatment of non-skin-related cancers. The drug targets several of the proteins that are known to be dysregulated in melanomas. The anti-tumor activity of cabozantinib was investigated using three human MBM cell lines. Cabozantinib treatment decreased the viability of all cell lines both when grown in monolayer cultures and as tumor spheroids. The in vitro cell migration was also inhibited and apoptosis was induced by cabozantinib. The phosphorylated RTKs p-PDGF-Rα, p-IGF-1R, p-MERTK and p-DDR1 were found to be downregulated in the p-RTK array of the MBM cells after cabozantinib treatment. Western blot validated these results and showed that cabozantinib treatment inhibited p-Akt and p-MEK 1/2. Further investigations are warranted to elucidate the therapeutic potential of cabozantinib for patients with MBM.     

Web-based self- and peer-assessment of teachers’ digital competencies

Although there exist several alternative frameworks and standards for describing the digital competencies expected from teachers, there is a lack of Web-based assessment tools that allow authentic, reliable and valid assessment of these competencies. This paper addresses the design challenges related to a software solution for self- and peer-assessment of teachers’ digital competencies. The empirical part of the paper describes the participatory design process and results from the first user testing of a Web-based self- and peer-assessment tool DigiMina, which supports teachers in building and sharing a personal competency profile. In DigiMina, the competencies are assessed by a teacher herself or by her peers using the performance indicators that are based on the competency model NETS for Teachers created by the International Society of Technology in Education.     

Tuning the Activity and Selectivity of CuCl2/γ-Al2O3 Ethene Oxychlorination Catalyst by Selective Promotion

CuCl₂/γ-Al₂O₃ catalysts with and without promoter metal chlorides (Cu5.0, K3.1Cu5.0, La10.9Cu5.0, Li0.5Cu5.0, Cs10.4Cu5.0, Mg1.9Cu5.0, Ce5.5La5.45Cu5.0, and K1.55La5.45Cu5.0) were studied for the ethene oxychlorination reaction in a fixed-bed reactor at 503 and 573 K, with C₂H₄:HCl:O₂:He = 1.0:1.1:0.38:14.4 (mole ratio), P(tot) = 1 atm and weight hourly space velocity (WHSV) = 1.5 g g^?1 h^?1 (based on ethene). It was found that all promoter metals enhanced the activity of the catalyst, as well as its selectivity towards the target product 1,2-dichloroethane (1,2-EDC). Co-promoted catalysts (K1.55La5.45Cu5.0 and Ce5.5La5.45Cu5.0) gave even higher activity and product selectivity than the single metal promoted catalysts. The activity of the CuCl₂/γ-Al₂O₃ catalyst, as well as the γ-Al₂O₃ support, both with and without metal chloride promoter(s), were further tested for 1,2-EDC conversion to byproducts in a fixed-bed reactor at 503 K, under a feed stream of 1,2-EDC:Ar = 1:11.5 (mole ratio), at P(tot) = 1 atm and WHSV = 1.5 g g^?1 h^?1 (based on 1,2-EDC). Prior to testing, the catalysts were pretreated in flowing ethene, HCl and/or O₂. It was observed that Lewis and Brønsted acid sites on the alumina surface were main reaction sites for conversion of 1,2-EDC to chlorinated byproducts: vinyl chloride monomer (VCM), 1,1-EDC, 1,2-dichloroethene (1,2-DCE) and ethyl chloride (EC) as well as dimerisation (butadiene) and aromatisation reactions (toluene), both with and without the presence of the Cu phase. The Cu phase was shown to contribute mainly to CO₂ and trichloroethane formation from 1,2-EDC via VCM. Co-promotion (K1.55La5.45Cu5.0) was found to enhance the activity of the Cu phase, and to mask acid sites on the alumina surface, thereby promoting ethene oxychlorination while at the same time hindering undesired conversion of the target product 1,2-EDC.     

A method for controller parameter estimation based on perturbations

Simulation and prediction of eigenfrequencies and mode shapes for active flexible multibody systems is an important task in disciplines such as robotics and aerospace engineering. A challenge is to accurately include both controller effects and flexible body dynamics in a multidisciplinary system model appropriate for modal analysis. A method for performing modal analyses of such systems in a finite element environment was recently developed by the authors. On issue is, however, that for engineers working in a finite element environment, the controller properties are not always explicitly available prior to modal analyses. The authors encountered this problem when working with the design of a particular offshore windmill. The controller for the windmill was delivered in the form of a dynamic link library (dll) from a third party provider, and when performing virtual testing of the windmill design, it was of great importance to use the “real” controller in the form of the provided dll, rather than re-model it in for instance Simulink or EASY5. This paper presents a method for estimating the controller parameters of PID-type controllers when solving the closed-loop eigenvalue problem for active flexible multibody systems in a finite element environment. The method is based on applying incremental changes, perturbations, to relevant system variables while recording reactions from other system variables. In this work, the theory of the method is derived and the method is tested through several numerical examples.     

Validation of a method for gas chromatographic analysis of eicosapentaenoic acid and docosahexaenoic acid as active ingredients in medicinal products

A gas chromatographic method for the determination of all-cis-5,8,11,14,17-eicosapentaenoic acid (EPA) and all-cis-4,7,10,13,16,19-docosahexaenoic acid (DHA) as active ingredients in medicinal products was developed and validated. In accordance with the rules governing medicinal products in the European Community, the method establishes relations between label claims of active ingredients and known reference standards. A routine for examining instrument status is proposed. The relative standard deviation was 1% (n=26) for determination of the empirical response factors of EPA ethyl ester and DHA ethyl ester relative to the internal standard, C23:0 methyl ester. This experiment included two columns and EPA and DHA standards from two different suppliers and was carried out over a five-month period. Repeatability (n=6) for low and medium concentrates of glycerides and high concentrates of ethyl esters, expressed as coefficient of variation, was 4, 0.7 and 0.7%, respectively. Accuracy (n=6) determined as percent recovery was better than 98% for all sample types. Analytical results from a twelve-month stability study of the high concentrate are shown. Presented at the AOCS Annual Meeting in Chicago, IL, May 1991.